FactCHD: Benchmarking Fact-Conflicting Hallucination Detection

Xiang Chen♠♣ , Duanzheng Song , Honghao Gui♠♣ , Chenxi Wang♠♣ , Ningyu Zhang♠♣* , Yong Jiang , Fei Huang , Chengfei Lv , Dan Zhang , Huajun Chen♠♡♣* ,

Zhejiang University Donghai Laboratory. Alibaba Group Zhejiang University - Ant Group Joint Laboratory of Knowledge Graph
*Corresponding Author

Abstract

Despite their impressive generative capabilities, LLMs are hindered by fact-conflicting hallucinations in real-world applications. The accurate identification of hallucinations in texts generated by LLMs, especially in complex inferential scenarios, is a relatively unexplored area. To address this gap, we present FactCHD, a dedicated benchmark designed for the detection of fact-conflicting hallucinations from LLMs. FactCHD features a diverse dataset that spans various factuality patterns, including vanilla, multi-hop, comparison, and set opera- tion. A distinctive element of FactCHD is its integration of fact-based evidence chains, significantly enhancing the depth of evaluating the detectors’ explanations. Experiments on different LLMs expose the shortcomings of current approaches in detecting factual errors accurately. Furthermore, we introduce TRUTH-TRIANGULATOR that synthesizes reflective considerations by tool-enhanced ChatGPT and LoRA-tuning based on Llama2, aiming to yield more credible detection through the amalgamation of predictive results and evidence.



Hallucination Detection

Figure 1: Illustration of fact-conflicting hallucination detection example from FACTCHD, where the green part represents factual explanation core (body part) in the chain of evidence.




FactCHD Construction

Figure 2: Overview of the construction process of FactCHD.


We develop FactCHD, a dataset containing a wealth of training instances and an additional 6,960 carefully selected samples for evaluating fact-conflicting hallucinations from LLMs. Our dataset maintains a balanced representation of FACTUAL and NON-FACTUAL categories, offering a robust framework for assessment. The statistics and domain distribution of FactCHD are depicted in Figure 2.


TRUTH-TRIANGULATOR Framework

Figure 3: Overview TRUTH-TRIANGULATOR. Here we designate the “Truth Guardian” based on Llama2-7B-chat-LoRA while the “Truth Seeker” based on GPT-3.5-turbo (tool) in our experiments. We want the “Fact Verdict Manager” to collect evidence from different viewpoints to enhance the reliability and accuracy of the obtained conclusion.


We categorize tool-enhanced ChatGPT as the Truth Seeker, which aims to make informed judgments by seeking external knowledge. However, the information returned by exter- nal knowledge sources may inevitably be incomplete, erroneous, or redundant, thus potentially misleading the large-scale model. On the other hand, the detect-specific expert as the Truth Guardian relies on its knowledge and expertise in the task, tending towards more conservative predictions. To address these challenges, we propose the TRUTH- TRIANGULATOR framework inspired by the “Triangulation for Truth” theory, involving verifying and confirming information by cross-referencing multiple independent perspectives.


Main Results

Table 1: Results on FACTCLS and EXPMATCH (abbreviated as CLS. and EXP.) along with FACTCHD estimated by each method.




Analysis

Figure 2: Case analysis of out-of-distribution examples from ChatGPT using TRUTH-TRIANGULATOR.


BibTeX


    @article{chen2024factchd,
        title={FactCHD: Benchmarking Fact-Conflicting Hallucination Detection}, 
        author={Xiang Chen and Duanzheng Song and Honghao Gui and Chenxi Wang and Ningyu Zhang and 
          Jiang Yong and Fei Huang and Chengfei Lv and Dan Zhang and Huajun Chen},
        year={2024},
        eprint={2310.12086},
        archivePrefix={arXiv},
        primaryClass={cs.CL}
  }

This website is adapted from Nerfies, licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.